Thread-controlling mechanism for overedge sewing machines



Sept. 29; 1942. N. KNAUS 2,297,061

THREAD-CONTROLLING MECHANISMS FOR OVEREDGE SEWING MACHINES Filed April 17, 1941 2 Sheets-Sheet l N. KNAUS Sept. 29, 1942.

THREAD-CONTROLLING MECHANISMS FOR OVEREDGE SEWING MACHINES Filed April 17, 1941 2 Sheets-Sheet 2 Mow;

Patented Sept. 29, 1942 THREAD-CONTROLLING MECHANISM FOR OVEREDG E SEWING MACHINES Nicholaus Knaus, Newark, N. assignor to The Singer Manufacturing Company, N. J., a corporation of New Jersey Elizabeth,

Application April 17, 1941, Serial Ne. 388,968

10 Claims. (01.112-162) This invention relates to overedge sewing machines, more particularly of the type disclosed in my United States Patent No. 2,238,796, April 15, 1941.

The invention has for an object to provide an improved, simplified and eflicient threadeontrolling mechanism for overedge sewing machine of this type which is adaptable to stitching requirements on various materials as well as meeting the requirements for sewing an elastic chain in the air in chaining off operations between successive work pieces. n

One of the principal objects of the invention is to provide thread-controlling mechanism for the above mentioned type of overedge sewing ma-.

chines which, although having certain elements common to the threads for both loopers, nevertheless provides an independent control for each looper thread and affords means for readily adjusting the action of each control means independently of the other, thereby to adapt the machine to various materials and work conditions.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art. A

In the accompanying drawings, Fig. 1 is a front side elevation of an overedge sewing machine embodying the present invention. Fig. 2 is a detail front view of elements of the stitchforming mechanism and the improved threadcontrolling mechanism, the parts being in positions advanced from those shown in Fig. 1. Fig. 3 is a view similar to Fig. 2, with the parts in still further advanced positions. Fig. 4 is a vertical section taken substantially on the line 4-4 of Fig. 1. Fig. 5 is a disassembled perspective view of certain elements of the controlling mechanism for the two looper threads.' Fig. 6 is an enlarged vertical sectional view taken substantially on the line 6-6 of Fig. 3 showing the means for effecting simultaneous adjustment of two of the normally fixed thread-eyes in the looper-thread controlling mechanism.

Referring more specifically to the drawings, the invention is illustrated as embodied in an overedge sewing machine comprising a frame I, in the nature of a hollow casing, in which is joumaled a horizontally disposed main-shaft 2,

adapted to be rotated from any suitable source of power by a belt 3 engaging the combined pulleyand hand-wheel P. Journaled horizontally in the frame I and actuated from the mainshaft 2, by mechanism not shown herein but illustrated and described in my above mentioned patent application, is an arm 5 in which is secured a curved eye-pointed needle 6, carrying a thread t, adapted to penetrate the work 20 and cooperate with an underedge looper 1, carryinga thread it, and an overedge looper 8, having an eye 8 carrying a thread 0, in the formation of overedge and chaining-01f" stitches.

The under looper I is secured in a looper-carrier 9 fixed upon a rock-shaft l5 joumaled horizontally in the machine frame transversely of the main-shaft 2. oscillatory movements are given to the shaft I5, and the looper-carrier 9 secured thereto, from a crank 4, formed on the main-shaft, through the medium of a pitman l8 connected at one end to said: crank and at its other end to the free end of a rock-arm l1 secured upon the shaft l5, all as shown inmy above mentioned patent.

The overedge looper 8 is secured in a carrier-lever l4 pivoted at III to a sleeve l5 which is slidingly supported by a pin l3 carried by the frame I. The lever I4 is pivotally connected, at l2, to the free end of an arm l9 fixed to a rockshaft 20 joumaled horizontally in the frame I beneath and transversely of the main-shaft 2.

Also secured to the shaft 20, is a crank-arm 2| which is connected, by a ball joint 22, with the lower end of a pitman 23 the upper end of which embraces a crank 24 formed on the main-shaft 2. From the foregoing it will be understood that the under looper 'l is given oscillatory movements about the axis of shaft l5 from the crank 4 on the main-shaft while the overedge looper 8 is given combined longitudinal movements lengthwise of the pin l3 and oscillatory movements about the pivot ID from the crank 24 on the main-shaft.

The machine also includes a work-trimming mechanism located in advance of the stitchforming mechanism and comprising a normally stationary lower trimmer blade L and a cooperating upper vibrating trimmer blade U which is actuated from the main-shaft 2. A sheetmetal guard-plate G is secured to the forward face of the main frame to prevent accidental contact with the looper and trimmer mechanisms.

Adjustably secured to the forward end of rock-shaft 20, by clamp screw 25 (see Fig. 4),

are two thread-controlling arms 26 and 21 having offset portions 26 and- 21 respectively,

which project through an arcuate slot 28 formed in a cover-plate 29 secured to the front face of the machine frame forwardly of a cavity 30 therein in which are located the rock-arms l1 and I9 and parts connected therewith. The portion 26 is provided with thread-eyes 26 and 26 and the portion 21 is provided with a single thread-eye 21 I The thread-controlling arms 26 and 21 are of unequal length and therefore may be adjusted angularly about the axis of the shaft 26, relative to each other, to vary their actions on the threads u and 0, without causing interference between their offset ends 26 and 21 The arm 26 is not only adjustable angularly about the axis of shaft 20, but it is also adjustable lengthwise of itself to vary the extent of movement of the thread-eyes 26 and 26 To permit the arm 26 to be adjusted lengthwise, the lower end thereof is provided with a clearance slot 26 through which the shank of the clamp-screw 25 passes.

The plate 29 has secured thereto fixed pins 3| and 32 having thread-guiding eyes 3|, 3| and 32 32 respectively, and an upwardly and forwardlyextending thread-guiding tube 33. The plate 29 also has adjustably secured to it, at the rear side thereof, a, plate 34-which carries pins 35 and 36 which project through slots 31 and 36, respectively, in the plate 29 and have in their outer ends thread-guiding eyes 35 and 36 for the under looper thread u. The plate 34 is vertically adjustable on the plate 29 and is held in adjusted position by means of a clamp screw 39, the shank of which passes through a slot 40 in the plate 29 and is threaded into a tapped hole 4| in the plate 34. Fixed to forward end of rockshaft I5, which actuates the under looper 1, is one end of a thread-controlling arm 42 the other end 42 of which is offset and projects outwardly through an arcuate slot 43 formed in the coverplate 29. The end 42 is provided with a threadeye 42- and oscillatory motions of the looperactuating rock-shaft causes that thread-eye to be moved substantially vertically between the thread-eyes 35 and 36' for a purpose hereinafter to be described. Cover-plate 29 is also provided with a circular opening 29 through which the head of clamp screw 25 projects to facilitate adjustment of the thread-controlling arms 26 and 21.

The guard-plate G, hereinbefore mentioned, carries at its rear side, a horizontally disposed thread-guiding tube 44 one end of which fits into a recess 45 formed in the face of cover-plate 29 to receive the looper-thread u, from the threadeye 36. From the other end of the tube 44 the thread it runs through a vertical slot 46 in the machine frame and thence through a second thread-guiding tube 41 from which it extends to the eye 1 of the looper I.

To thread the machine, preparatory to a sewing operation, the needle thread t is drawn from a suitable supply and passed through threadtension 48, thread-guiding tube 49, thread-eye 50 formed in an arm extending upwardly from the tube 49, and thence through the eye of the needle. The under looper thread u is drawn from a suitable supply'and passed through thread-eye 52, tension 53, thread-eyes 3|, 26, 32', 35, 42', 36, tube 44, slot 46, tube 41 and eye 1 of the looper 1. The overedge looper thread 0 is drawn from a source of supply and passed through 32', '21", tube 33, to the eye 8 of the overedge looper 3. 1

Operation Starting with the parts in the positions shown in Fig. 1 in which the needle 6 is slightly advanced from its uppermost position, the under thread-eye 54, tension 55, thread-eyes 3l 26 looper 1 is partially retracted and the overedge looper l is fully advanced and, together with its thread 0, extends through a loop of the thread it between the eye of the looper 1 and the work, a typical operationof the stitch-forming elements and thread-controlling mechanism when operating on one type of material is as follows: During the first 45 degrees of rotation of the main shaft, the overedge looper is retracted and the needle descends and enters a loop formed in the overedge looper thread 0; the under looper 1 is further retracted; take-up arm 26, (specifically the offset portion 26 thereof having the threadeyes 26 and 26') moves counterclockwise, as seen in Fig. 1, to a position beneath or slightly beyond the thread-guide 3| but in so moving has no material effect upon the threads u and o; the take-up arm 21 (specifically the offset portion 21 thereof having thread-eye 21) moves counterclockwise toward a straight line between thread-guides 32 and 33 and therefore gives up thread to the overedge looper 8 to permit the formation of the overedge stitch; take-up arm 42 is moved counterclockwise thereby receding from thread-guides 35 and 36 and taking up slack in the thread it caused by retraction of the looper 1.

During-the second 45 degrees of rotation of the main shaft, which brings the parts to the positions shown in Fig. 2, the needle continues to descend; the overedge ooper continues to retract; the under looper is f y retracted; take-up 42 continues to take up on thread 9 and, after the stitch is tightened, pulls from the supply a portion of the thread required for the next succeeding stitch; take-up 21 continues to give up thread; and take-up 26 takes up slack produced in thread 0 by take-up 21 and pulls off from the supply the balance of the thread u required for the next succeeding stitch.

Th third 45 degrees of rotation of the main shaft causes the needle to be moved to its lowermost position; the under looper starts to advance; the overedge looper continues to be retracted; take-up 26 takes up on threads u and o; take-up 21 continues to give up thread; and take-up 42 is moved downwardly and gives up thread 11. to advancing looper I.

During the fourth- 45 degrees of rotation of the main shaft, which brings the parts to the positions shown in Fig. 3, the needle is partially retracted and forms a loop in its thread it; the under looperis advanced and carries'lts thread u through the needle-thread loop; the overedge looper is fully retracted; take-ups 21 and 42 continue to give up thread; take-up 26 takes up on threads u and o and, as its take-up action is faster than the give up action of take-up 21, it draws a length of thread .0 from the source of supply to form the next succeeding stitch.

The cycle of operation is'nowone-half completed and the parts are in the positions illustrated in Fig. 3. Rotation of the main shaft through the next degrees causes the needle to be partially retracted; the under looper is advanced to its extreme forward position; the overedge looper is advanced and carries its thread into and partially through a loop of the under looper thread; take-ups 26 and 21 are rotated clockwise, the former giving up thread to the advancing loopers I and 3 while the latter has I a slight take-up action on the overedge looper thread to control the slack therein; take-up 42 is moved downwardly to its lowermost position and gives up thread it to the advancing under looper I.

The next 90 degrees of rotation brings the parts back to the starting position shown in Fig. 1. During that rotation the needle is fully retracted and then advanced slightly; the under looper is partially retracted; the overedge looper is advanced to its extreme forward position and carries its thread through the loop of the under thread. which then overlies the overedge looper as indicated in Fig. 1; take-up 26 gives up slack on thread it and o; take-up 2! takes up and controls the slack in thread 0; and take-up 42 moves upwardly and takes up the slack in thread it of the receding under looper 1.

The foregoing describes the actions of the parts in a given setting of the take-ups 26 and 21 and the adjustable thread-guides 35 and 36 to adapt the machine to produce a specific sewing operation on a specific type of material, such for example as knit goods. It will readily be perceived that the above described operation may be modified by relative angular adjustment of the take-ups '26 and 21 on the rock-shaft 20. Likewise the amount of take-up action of the take-up 26 may be varied by lengthwise adjustment thereof as above described. The adjustment of the thread-guides 35 and 36 is utilized primarily to position, relative to the edge of work, the purl which is produced by the interlocking of the under thread a and the overedge thread 0. With the thread-guides 35 and 36 adjusted to their uppermost position the amount of thread u drawn from the supply by the take-up 42 is relatively small and in work of a given thickness the purl is positioned along the edge of the work.

'When the thread-guides 35 and 36 are shifted to their lowermost position the take-up arm 42 willdraw a greater amount of thread from the supply and therefore the thread it will extend from the point of concatenation with the needle thread under and around the edge of the work and to a position between the edge of the work and the line of penetration of the needle. This will cause the purl to be laid on the top of the work inwardly from the edge thereof. The purl may be laid at positions intermediate these two extreme positions by intermediate adjustments of the thread-guides 35 and 36. It will be understood that the amount of overedge thread 0 which will be used in making a stitch will be indirectly proportionate to the amount of under thread used. The thread-guides 35 and 36 also may be adjusted to position the purl when work of difi'erent character or thickness is overedged.

Having thus set forth the nature of the invention, what I claim herein is:

1. A sewing machine having an endwise reciprocatory needle, an under looper and an overedge looper each carrying a thread, a pair of rock-shafts each connected to actuate a respective one of said loopers, a pair of take-up arms secured to and actuated by one of said rockshafts, one of said take-up arms acting on both of said looper-threads and the other acting on only one of said threads, means to effect relative angular adjustment between said take-uparms to vary their actions on the threads, and means to guide said looper-threads to positions 2. A sewing machine having an endwise reciprocatory needle an under looper'and an overedge looper each carryinga thread, a pair of rock-shafts each connected to actuate 9. respective one of said loopers, a pairof'take-up arms secured to and actuated by one of said rockshafts, one of said take-up arms actingon both of said looper-threads and the other'acting on only one ofsaid threads, means to vary the effective lengthof one of said take-up arms thereby to vary its range of action, and means to guide said looper-threads to positions within the range of action of said take-up arms.

3. A sewing machine having an endwise-reciprocatory needle, an under looper and an overedge looper each carrying a thread, a pair'of rock-shafts each connected to actuate a respective one of said loopers, a pair of take-up arms secured to and actuated byone of said rock-shafts, one of said take-up arms acting on both of said looper-threads and the other acting on only one of said threads,- means to eflect angular adjustment of both of said take-up arms, means to vary the effective length of one of said take-up arms thereby to. varyits range of action, and means to guide said looper-threads to positions within the range of action of'said take-up arms.

4. A sewing machinehaving an endwise reciprocatory needle, an under looper and an overedge looper each carrying a thread, a pair of spaced rock-shafts each connected to actuate a respective one of said loopers, a pair of take-up arms actuated by one of said rock-shafts, one of said take-up arms actingon' both of said looper-threads and the\pther arm acting on only one of said threads, means for individually varying the action of each. of said pair of take-up arms, a single take-up arm actuated by the other within the range of action of said take-up arms.

of said rock-shafts and adapted to act on the under looper-thread, and means to guide said looper-threads to positions within the range of actionof said take-up arms.

5. A sewing machine having an endwise reciprocating needle, an under looper and an overedge looper each carrying a thread, a pair of spaced rock-shafts each connectedto actuate a respective one of said loopers, a pair of takeup arms adjustably secured to and actuated by one of saidrock-shafts, one of said take-up arms acting on both of .said looper-threads and the other arm acting on only the overedge looperthread, each of said take-up arms having," atits outer end, an oflset portion containing a threadeye, said take-up arms being of unequal lengths whereby they may be relatively adjusted about the axis of their supporting rock-shaft without causing interference between said offset portions, means for securing said take-up arms in their adjusted positions, and means to guide said looper-threads to positions within the range of action of said take-up arms.

6. A sewing machine having an endwise reciprocatory needle, an under looper and an overedge looper, a pair of spaced parallel rock-shafts each connected to actuate a respective one of said loopers, first and second looper-thread takeup arms connected with and actuated by one of said rock-shafts, thread-eyes in each of said take-up arms, first and second fixed threadguides located at opposite sides of the path of movement of the thread-eyes in said first takeup. arm, the threads for both of said loopers passing through said first and second thread-- guides and through the thread-eye in said first take-up arm therebetween, a thread-guiding tube located intermediate the second thread-guide and the overedge looper for directing thread to said overedge looper, the thread in passing from said second thread-guide to said tube also passing through the thread-eye in said second take-up arm, means for guiding a thread from said secnd thread-guide to said under looper, and takearm acting on'only one of said threads, each of said take-up arms having, at its outer end, an oil'set portion provided with a thread-eye, means for relatively adjusting said take-up arms angularly about the axis of their supporting rock shaft, 9. single clamp-screw for locking both of said take-up arms in their adjusted positions, one of said take-up arms having a slot therein through which said clamp-screw passes, thereby permitting lengthwise adjustment of said arm in addition to its angular adjustment, and means to guide said looper-threads to positions within the range of action of said take-up arms.

8. A sewing machine having an endwise reciprocating needle, an under looper and an overedge looper each carrying a thread, a pair of rock-shafts each connected to actuate a respective one of said loopers, a pair of take-up arms actuated by one of said rock-shafts, one of said take-up arms acting on both of said looperthreads and the other acting on only one of said looper-threads, means for relatively adjusting said take-up arms to vary their actions on said threads, fixed thread-guides adapted to guide said threads to positions within the range of action of said take-up arms, a single take-up arm actuated by the other of said rock-shafts and having a thread-eye, a pair of normally fixed thread-guides located at opposite sides of the range of action of said thread-eye, and means to simultaneously adjust the position of both of said thread-guides relative to said movable thread-eye.

9. A sewing machine having a needle, an underlooper and an overedge looper each carrying a thread, a slotted plate, a pair of rock-shafts each connected to actuate a respective one of said loopers, a pair 01. take-up arms actuated by one of said rock-shafts and having thread-engaging portions projecting through said slotted plate, a plurality of fixed thread-guides carried by said plate for directing a looper-thread to a osition within the range of action of said takeup arms, a single take-up arm actuated by the other of said rock-shafts and having a single thread-engaging portion projecting through said slotted plate, a pair of thread-guides adjustably secured to said plate and located at opposite sides of the path of movement or the threadengaging portion of said single take-up arm,

. and means for simultaneously adjusting the position of both of saidpair of thread-guides.

10. A sewing machine comprising-a frame having a cavity in the forward-face thereof, a slotted cover-plate substantially closing said cavity, an under looper and an overedge looper each carrying'a, thread, a pair of rock-shafts each connected to actuate a respective one of said loopers, a pair of take-up arms located in said cavity and actuated by one of said rock-shafts, said take-up arms each having an offset portion projecting through said cover-plate and provided with a thread-eye, one of said take-up arms acting on both of said looper-threads and the other acting on only one looper-thread, a plurality of fixed thread-guides carried by said cover-plate for directing said looper-threads to a position within the range of action of said take-up arms, a single take-up arm located within said cavity and actuated by the other of said rock-shafts and having an offset portion, provided with a thread-eye, projecting through said cover-plate, a thread-guide supporting plate adjustably secured upon the rear side of said cover-plate, a pair of thread-guides secured to said supporting plate and projecting through said cover-plate to positions at opposite sides of the thread-eye in said single take-up arm, and means to effect adjustment of said supporting plate to vary the position of said pair of thread-guides relative to the thread-eye in said single take-up.

NICHOLAUS KNAUS. 

